Case Study

The United States'worst-ever chlorine
gas leak killed nine people and injured 250. Eighteen months later -
despite efforts to clean and restore the textile mill affected by the
leak - 4,000 people lost their jobs, and a longtime, family-owned
textile company went out of business.

Perhaps the only good thing to come out of the disaster
is that, if such an accident occurs again, authorities will have better
guidelines for first responders and cleanup crews. These guidelines
will be the product of about two years of testing and research by
scientists and engineers at the Georgia Tech Research Institute (GTRI)
and the Georgia Institute of Technology.

GTRI scientists and engineers from Georgia Tech's
National Electric Energy Testing, Research and Applications Center
(NEETRAC) first became involved in cleanup efforts within a few days
after the train wreck that caused the leak on Jan. 6, 2005, in the
small town of Graniteville, S.C. South Carolina Electric & Gas
needed advice, as well as analysis of components from its heavily
damaged power substations that served Graniteville and the large, local
textile facility owned by Avondale Mills. The 70 to 80 tons of chlorine
gas that leaked from the wrecked train corroded equipment in the
substations, which eventually had to be rebuilt.

Because of the magnitude of the disaster, emergency
response activities delayed cleanup crews' access to the substations
and textile mill. It was 17 days after the accident before clean up
began at Avondale, which, by early February 2005, had contracted with
GTRI to do materials testing and assessment of restoration efforts.

"Basically, you had items sitting in an acid bottle for
days," says Lisa Detter-Hoskin, a GTRI senior research scientist who
led the research. "Chlorine combined with moisture in the air to form
acids that corrosively ate away at surfaces and moved inward like a
cancer in the human body. Much of the mill's equipment was beyond
repair due to the severity of the chlorine attack."

Early in the research, it became
apparent that the far-reaching effects of the chlorine accident on
Avondale would require a variety of expertise from GTRI, Georgia Tech
and elsewhere. So Avondale's law firm, King & Spalding in Atlanta,
hired Detter-Hoskin as a consultant to coordinate environmental and
materials-related testing and find appropriate experts - among them, chemists, environmental scientists, civil
engineers, air quality monitoring specialists, metallurgists, water
treatment experts and industrial hygienists. Detter-Hoskin, group
leader of the GTRI Materials Analysis Center, also performed materials
analysis and corrosion testing on behalf of Avondale and provided
technical consultation for chemical cleanup and restoration.

Detter-Hoskin compiled all of the research and
recommendations into a report for Avondale. That report is now the
basis for a white paper Detter-Hoskin - a Ph.D.-level inorganic chemist
with almost 20 years of experience in dealing with materials forensics,
including chlorine corrosion - is writing for the U.S. Department of
Homeland Security. She will explain the relationship between acid
concentration, exposure effects and possible degrees of material
damage. She also will document the cleaning protocols most effective to
decontaminate and restore an area affected by a chlorine leak.
Detter-Hoskin believes that paper will ultimately become a handbook for
first responders, disaster cleanup companies and the chemical industry.

"Chlorine and other highly reactive chemicals are of
great concern because they're shipped daily by rail, barge and truck,"
Detter-Hoskin says. "There have been some leaks in U.S. history, but
until Graniteville, they were mostly small, and little damage was done.
So there was very little public information on how to best serve
Avondale Mills in this accident."

Now, GTRI and Georgia Tech have a unique database of
information resulting from 18 months of testing and assessment of
samples from Avondale's Graniteville facilities. This information may
be able to help in the event of another accident, or even a terrorist
attack, Detter-Hoskin says.

The accident and subsequent cleanup efforts also
revealed some areas of potential future research for GTRI and Georgia
Tech, including technology to improve the safety of shipping chlorine,
Detter-Hoskin notes. Research might also focus on the development of
safer chemical alternatives to chlorine, which is currently used in 27
percent of all U.S. manufacturing operations, including the
sanitization, pharmaceutical and automotive industries.

In the meantime, Detter-Hoskin is reviewing the details
of and gleaning the lessons learned from the Graniteville disaster.
Numerous factors contributed to the wide-ranging impact of the chlorine
leak, she says. For one, the weather in Graniteville at the time of the
accident was warm and humid, and there was no breeze that might have
dispersed the gas.

"The gas had plenty of moisture to react with, in
addition to particulates in the air," Detter-Hoskin explains. "Chlorine
will react with almost anything to transform it into more reactive
chlorine derivatives. So, dust, lint and dirt in the mill all became
chlorinated."

In addition, process chemicals used in the mill, such
as those for dyeing fabrics, became chlorinated and subsequently super
reactive. "So you weren't just dealing with chlorine leaking from the
rail car. Chlorine was reacting with everything, including coal, gas
and oil fueling the boilers," she says.

Another factor negatively affecting cleanup was the
delay in getting initial access to the mill and the ineffective cleanup
process that was implemented, Detter-Hoskin says. "The severe,
chlorine-induced corrosion was prolonged because the damage was not
mitigated in a timely manner," she adds.

Norfolk Southern was in charge
of the initial cleanup efforts at Avondale. According to Detter-Hoskin,
their cleaning protocols lacked ongoing environmental abatement, such
as that used in lead paint or asbestos remediation. This allowed
chlorinated dirt and lint to be redistributed onto cleaned surfaces.
Also, limited mechanical or abrasive steps were used to pre-clean
material surfaces, and they did not perform any deep chemical cleaning
with strong acids or bases.

"The phosphate-based restoration process was selected
because it is environmentally friendly, safer for workers and commonly
employed after chlorine chemical fires," Detter-Hoskins says. "But
these chlorine fires do not cause the extreme deep-metal pitting damage
observed at Avondale Mills. The phosphate cleaning methods do not
aggressively get into metal layers to clean the chlorine acidic salts
deep within pits. The process they used actually encapsulated a lot of
chlorine debris. In the long run, that exacerbated cleanup attempts."

Detter-Hoskin recommended implementing two alternative
rigorous cleaning methods approved by the American Society for Testing
and Materials and the Society for Protective Coatings. These processes
would have required skilled workers and costly hazardous acidic waste
disposal. But by May 2006, when Avondale Mills settled with its
insurance company, damage to equipment in the mill was beyond repair,
Detter-Hoskin says. Two months later the company went out of business.

Avondale has a federal lawsuit pending against Norfolk
Southern and the three workers who left open the manual switch, leading
to the train wreck. That case will be tried in federal court in Aiken,
S.C., but it may be many years before it's resolved, Detter-Hoskin
says. She will serve as a lead scientific expert for Avondale in the
trial.

"This accident happened in the small community of
Graniteville, South Carolina, and in my estimate, its ultimate economic
impact to the town will likely exceed $1 billion," Detter-Hoskin says.
"Had this occurred in Atlanta or another large city, you would have had
hundreds of thousands of people hurt and killed within a 10-minute
period. The financial impact would be immense, as well. Metal equipment
and electrical wiring would be destroyed, and computer data would be
lost."